Adapted from Barbecue USA. To set up a three-zone fire on a charcoal grill, rake half the lit coals into a double layer on one-third of the bottom grate. The rest of the coals go in a single layer in the center; the other third of the grate should have no coals. This gives you three different heat zones--a hot zone for searing, a medium zone for cooking, and a safety zone for holding food. Prep time includes marinating time.